Four-lamp explosion-proof fluorescent fixtures presently in common use have four transparent glass sleeves, each of which surrounds one fluorescent lamp. Each sleeve is conventionally flared at both ends, and rests against a shoulder integral with a wall of an end housing at each end of the fixture. This sleeve is cemented into an aperture inboard of the shoulder in the long dimension of the fixture, while the unconnected end housings are held in a jig or fixture, and a ballast housing is fastened to and between the two end housings after the sleeves have been cemented. Although such conventional fixtures can be relamped through the open ends of the sleeves, if one of the sleeves must be replaced, all of the sleeves have to be broken. The conventional explosion-proof fluorescent fixtures use a standard forty-eight inch tube, which makes the lamp fixture about fifty-two inches overall in length.
One of the objects of this invention is to provide an explosion-proof fixture in which a single sleeve can be replaced without breaking either that sleeve or any other sleeve in the fixture.
Another object is to provide such a fixture that permits preassembly of two end housings and one or more ballast or wire housings before the sleeve is mounted.
Still another object is to provide such a fixture that is more compact, providing greater lumen output in a smaller fixture, than fixtures known heretofore.
Still another object is to provide such a fixture that is easy to assemble and strong compared with explosion-proof fluorescent fixtures known heretofore.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.